The turbine shrouds surrounding turbine rotors are normally segmented in the circumferential direction to allow for thermal expansion. Being exposed to very hot combustion gasses, the turbine shrouds usually need to be cooled. Since flowing coolant through a shroud assembly diminishes overall engine performance, it is desirable to minimize cooling flow consumption without degrading shroud segment durability. Individual feather seals are typically installed in confronting slots defined in the end walls of circumferentially adjacent turbine shroud segments to prevent undesirable cooling flow leakage at the inter-segment gaps between adjacent shroud segments. While such feather seal arrangements generally provide adequate inter-segment sealing, there is a continued need to provide better sealing and, thus, minimize coolant flow consumption.
It has also been found through thermal analysis that relatively hot spots can occur in the slotted end wall regions of the shroud segments. The slot which accepts the feather seal breaks the heat flow path from the radially inner hot gaspath side of the segment to the radially outer cooled side thereof. Accordingly, in some cases, the segment may be not sufficiently cooled at this feather seal location.
There is thus a need to provide an improved turbine shroud arrangement which addresses theses and other limitations of the prior art.